The Somali militant group al-Shabab has claimed responsibility for a suicide bomb attack in Mogadishu that killed at least 60 people.

Witnesses told VOA's Somali service that two suicide bombers drove a truck into a compound housing Somali government offices. Officials say most of the victims were students who had come to the Ministry of Education to learn the results of exams to study abroad.

The al-Qaida-linked militant group al-Shabab claimed responsibility for the bombing.

Watch video of the explosion and the immediate aftermath. Warning: contains some graphic images.

The attack is the first in Mogadishu since Somalia's Transitional Federal Government announced in August that it had driven al-Shabab out of the capital, following a successful military operation by government and African Union forces.

Officials at the time said the military victory marked the beginning of the end of al-Shabab.

But, the director of the Africa Center at the Atlantic Council in Washington, J. Peter Pham, says the militants may be reverting back to a strategy that worked better for them against foreign militaries in the past.

“Certainly, Al Shabab, when it withdrew from Mogadishu at the beginning of August, several of its leaders threatened to adopt exactly this type of tactic, this type of irregular warfare that had proved so successful against the Ethiopians,” said Pham.

Ethiopian troops helped the TFG battle al-Shabab for two years before withdrawing from Somalia in early 2009.

Pham says it is not yet clear whether al-Shabab, which has lost resources and popular support in recent months, has the ability to sustain a renewed campaign of violence.

But, he says, the TFG has failed to take advantage of its opponent's weaknesses.

“What they should be doing is building up on local support, extending services and presence in the areas that were opened up by Shabab, that's what a government interested in fighting an insurgency would do," he added. "However, knowing the TFG, looking at their record, if this was a wake-up call, I suspect that they've already reached over and hit the snooze alarm.”